Cameras have been widely applied as a standard configuration to a variety of terminal devices, such as mobile phones. The cameras implemented in the terminal device include a front camera and a rear camera, which are arranged at the front surface and the rear surface of the terminal device, respectively. The front camera is used for self-portraits and conference meetings, whereas the rear camera is used for general photography.
The rear camera is taken as an example and explained as follows. In the rear camera, both a viewport cover plate and the rear camera are installed in a front housing. Moreover, both of them are positioned by their individual overall dimensions. The viewport cover plate is a protective glass of a touch screen, and is printed thereon with a display screen area, a camera area, an icon area, etc., wherein the camera area is also called as an external viewport. With the user's increasing requirement for the terminal device appearance, there is a higher demand for the concentricity between the optical centre of the camera and the centre of the external viewport. Moreover, there are more and more negative user experiences because of camera deviation, i.e., concentricity error.
With the limitation of the above techniques, and the unavoidable machining tolerance of each component during production, in order to avoid the phenomenon of severe concentricity deviation between the optical centre of the camera and the centre of the external viewport, it is necessary to increase the machining accuracy and decrease the machining tolerance. The phenomenon of concentricity deviation can only be reduced, but cannot be avoided. In a mass production processing, it particularly shows regularities of distribution suggesting that some products may have an excellent yield rate, and others may not. Once the assembling is completed, the status of the concentricity deviation is fixed and cannot be adjusted. Those products having a high concentricity deviation may only be scraped or remanufactured, thus causing a high rejection rate.